Valve for rock drills



F 2 1 4.5. w; E. 'CARR 2,36 ,7 vALyE FOR ROCK DRILLS F iled Sept. 30, 1945 49 4o 46 "65 I I W.

"INVENTOFP Halteul'ldarr.

rus ATTORNEY- v piston chamber.

Patented Feb. 20, 1945 VALVE FOR ROQK DBILLS Walter ErCarr, Spokane, Wash., assignor to Ingersoll-Rand Company, New York, N. Y., a corporation of New Jersey A This invention relates to rock drills, andmore particularly to a distributing valve for a fluid actuated rock drill of the reciprocatory piston type. I I

One object of the invention is.to obtain a light weight valve capable of effecting a rapid Figures 1 and 2 are longitudinal elevations,

partly broken away, of a rock drill equipped with distribution of pressure fluid to the piston chamber with a minimum lift of the valve.

valve mechanism constructed in accordance with thepractice of the invention and respectively showing the valve in positions to admit pressure fluid to the rear and front ends of the-piston chamber, and

Figure 3 is a perspective view, partly broken away, of the distributingvalve.

Referring more. particularly to the drawing,

munication with a pressure fluid supply port 38 in the wall of the cylinder 2!, and a throttle valve 39 rotatable in the adjacent portion of the cylinder 2| controls communicationbetween the port 38 and a source of pressure fluid supply (not shown).

The valve mechanism 3| constructed in accordance with the practice of the invention comprises an intermediate plate 40 and front and rear. plates 4! and 42, respectively. The rear plate 42, upon which the ratchet ring 32 rests, acts as a bearing for the forward surface of the head 33 and has an integral hollow stem 43 that extends throughthe plate 40 and into the plate 4| and serves as a bearing 44 for the rifle bar 34. The front end of the plate 40 is recessed to provide an annular valve chamber 45 and supply 20 designates, in general, a rock-drill comprising well known manner. Y

The cylinder 2| is .bored to provide a piston chamber 23 for the'acoommodation of a recip- -rocatory hammer piston 24 and has a free exhaust port 25 that ishontrolled by the piston 24. The piston is shown as being of the differential typehaving a head 26 and a stem 21 that extends slidably through a front cylinder washer 28 forming a closure for the frontend of the In the rearward endof the cylinder is an en larged bore 29 to accommodate rotation mecha nism 30 and valve mechanism 3!, the latter being arranged adjacent the rearward end of the piston chamber 23. The rotation mechanism is' shown as being of a well known type including a ratchet ring 32 that rests upon the valve mechanism 3l and in turn serves as a seat for the back head 22. Withinthe ratchet ring 32 is a head 33 of a rifle bar 34 that extends through the valve mechanism and is in fluted engagement with the hammer piston 24, as i customary.

The'head 33'carries the usual pawls 35 to coop eratewith teeth 36 on the inner surface of the ratchet ring'32 for determining the direction of rotation, of the rifle bar 34 and thus of the pischambers 46 and 41 that open into the valve chamber 45 and lie, respectively, outside and inside of said valve chamber.- The supply chamber 41 is in constant communication with the annular groove 31 in the ratchet ring through an annular passage 48 defined by the plates 40-42 and thestem 43 and through passages 49 in the plate 42 and the ratchet ring 32. Pressure fluid is conveyed to the supply chamber 46 by passages 50 in the plate 40 leading from the annular passage 48 to said suppl chamber.

In the front and rear ends of the valve chamber 45 are annular grooves 5i and 52, respectively, and from the groove 5| lead a plurality of inlet passages 53 to the rearward end'of the piston'chamber 23 to convey pressure fluid thereto for driving the piston 24 forwardly on its working stroke. The pressure fluid serving to actuate the piston rearwardly is conveyed to the front end of the piston chamber 23 by. an inlet passage'54 in' the Wall of the cylinder 2i com- 'municatingwith the annular groove 52 through a passage, or passages 55 in the'plate 40.

The open side of the groove 5! adjacent the valve chamber45 is flared having inner and outer bevelled surfaces 56 and'51 that constitute seats for correspondingly shaped surfaces 58'on the front end of a valve 59 reciprocable in the valve chamber for controlling the flow oi pressure fluid to the inlet passages. In like manner, inner and outer bevelled surfaces 60 and 6| are formed around the mouthof the groove 52 toserve as seats for bevelled surfaces 62' on th rearward side of the valve 59. Y

In the form of the invention'illustrated, the valve 59 consists of a ring-shaped member the peripheral surface 63 of which is slidable upon The front and rear ends of the valve con stitute actuating and holding surfaces 68 and 69, respectively. They are subjected to air compressed in the piston chamber bythe piston for throwing the valve to its limiting position and to the pressure fluid flowing from the supply chambers to the inlet passages for'holding the valve in such limiting positions.

The operation of the device is as follows: With the valve in the rearmost limiting position illustrated in Figure 1 of the drawing, pressure fluid flows from the supply chambers 46 and ill through the groove 5! and the inlet passages 53 into the rearwardend of the piston chamber and drives the piston 24 forwardly on its working stroke. The valve will remain in this position and pressure fluid will continue to flow into the rearward end of the piston chamber until the piston reaches a position where its rearward end will uncover the exhaust port 25. The pressure forwardly of the valve will then drop abruptly. At the same time the air forwardly of the exhaust port 25 will be compressed by the piston and such compression, acting against the actuating surface 69,'will throw the .valveforwardly against the seating surfaces 56 and 51;

i In the new position of the valve, pressure fluid flows from the supply chamber '41 through the space defined by thesurfaces 60 and 62 into the groove 52, thence'through-the passages 55 and 54 into the front; end of the piston chamber to drive the piston rearwardly to its initial position. When, during" its rearward stroke, the piston again uncovers the exhaust port 25 the pressure acting against thesurface 69 will drop and the air compressed in the rearward end of the piston chamber by-the piston and acting against the actuating surface 68 will then shift the valve rearwardly to its initial position against the seatin}; surfaces El) and El. During the subsequent charging of the rearward end of the piston chamber the valve will be held stationary by the pressure fluid flowing across the actuating surface 63 into the inlet passage 53.

From the foregoing description,'it will be apparent that the valve is particularly well suited for operation at low lift. This is due to the fact that a wide flow'area may be provided between pressure fluid supply and the inlet passages, the passages 53in the present instance, with a low lift of the valve. This is highly desirable, particularly during the charging of the rearward end of the piston chamber which is of large volume, ascompared with the front end, and permits of said rearward end of the piston chamber being charged in a minimum period of time.

I claim:

1. A fluid actuated rock drill, comprising a casing having a piston chamber and an exhaust port therefor, a reciprocatory piston in the piston chamber, a valve chest having a valve chamber, inlet passages leading from the valve chamber to the piston chamber, a pair of annular supply chambers for pressure fluid in the valve chest,

from the plate 40. The weight of the valve is and a valve in the valve chamber to uncover one supply chamber to admit pressure fluid to one inlet passage in one position of the valve and to uncover both supply chambers to admit pressure fluid to another inlet passage in another position of said valve.

2. A fluid actuated rock drill, comprising a casing having a piston chamber and an exhaust port therefor, a reciprocatory piston in the piston chamber, a valve chest having an annular valve chamber, a supply chamber opening into the inner side of the valve chamber, a supply chamber opening into the outer side of the valve chamber, inlet passages leading from the ends of the valve chamber to the piston chamber, and a valve to alternately uncover one supply chamberto admit pressure fluid into one inlet passage and to uncover both supply chambers to admit pressure fluid into the other inlet passage.

3. A fluid actuated rock drill, comprising a casing having a piston chamber and an exhaust port therefor, a reciprocatory piston in the piston chamber, a valve chest having an annular valve chamber, inlet passages leading from the valve chamber to the ends of the piston chamber, inner and outer annular supply chambers lying respec tively within and outside of the valve chamber and opening thereinto, and an annular valve to uncover the inner supply chamber to admit pressure fluid into one inlet passage in one position of the valve and to uncover both supply chambers to admit pressure fluid into the other inlet passage in another position of the valve.

4. A fluid actuated'rocl: drill, comprising a casing having a piston chamber and an exhaust port therefor, a reciprocatory piston in the piston chamber, a valve chest having an annular valve chamber, front and rear inlet passages leading from the valve chamber to the front and rear ends of the piston chamber, inner and outer supply chambers lying respectively inside and outside of the valve chamber and opening thereinto, and an annular valve to alternately uncover the inner supply chamber to admit pressure fluid into the front inlet passage and to uncover both supply chambers to admit pressure fluid into the rear inlet passage.

5. A fluid actuated rock drill, comprising a casing having a piston chamber and an exhaust port therefor, a reciprocatory piston in the piston chamber, a valve chest having an annular valve chamber, front and rear inlet passages leading from the valve chamber to the front and rear ends of the piston chamber, inner and outer supply chambers in the same transverse plane as the valve chamber lying respectively inside and out-.

side of the valve chamber and opening thereinto, a ring-shaped valve in the valve chamber to control communication between the outer supply chamber and the rear inlet passage, an introverted flange on the valve to control communication between the inner supply chamber and the rear inlet passage, and a second introverted flange on the valve to control communication between the inner supply'chamber and the front inlet passage.

6. A fluid actuated rock drill, comprising a casing having a piston chamber and an exhaust port therefor, a reciprocatory piston in the piston chamber, a valve chest having a pair of concentrically arranged supply chambers and a valve chamber between the supply chambers and opening thereinto, inlet passages leading from the valve chamber to the piston chamber, a ringshaped valve in the valve chamber to control communication between the outermost supply I "and a pair of supply chambers opening thereinto,

chamber and one inlet passage, an introverted passa e, and actuating surfaces subjected to compression flowing from the piston chamber for v throwing the valve to its limiting positions, said actuating surfaces being subjected to pressure fluid flowing to the inlet passages for holding the valve;

I 7. A fluidactuated rock drill, comprising a casing having a piston chamber and an exhaust port therefor, a reciprocatory piston in the piston chamber, a valve chest having a valve chamber I v and a pair of supply chambers opening intothe valve chamber, avalve in the valve chamber to valve pressure fluid from one supply chamber to one inlet passage in one position of the valve and to valve pressure fluid from both supply chain-- bers to the other inlet passage in anothersposition of the valve, and opposed actuating surfaces on the valve intermittently subjected to compression flowing from the piston chamber for throwing the valve and subjected to pressure fluid flowingto inlet passages leading from the valve chamber to the piston chamber, a ring-shaped valve to control communication between one supply chamber and one inlet passage and having a, laterally extending flange to control communication between the other supply-chamber and the said one inlet passage, and a second laterally extending flange on the valve to control communication between the said other supply chamber and another inlet passage.

'9. Afluidactuated rock drill, comprising a cas- 1 ing having apiston chamber and an exhaustport therefor, a reciprocatory piston in the piston chamber, a valve chest having a. valve chamber and a pair of'supply' chambers opening thereinto, inlet passages leading from the valve chamber to the piston chamber, a ring-shaped valve to control communication-between one supply chamber and one inlet passage and having a laterally extending flange to control communication between the other supply chamber and the said one inlet passage, a secondlaterally extendingflange the inlet passages for holding the valve in its limitingpositions. I

8. A fluid actuatedrock drill, comprising a casing having a piston chamber and an exhaust port therefor, a vreciprocatory piston in: the piston I chamber, a valve chesthaving a valve chamber iting positions.

on the valve to control communication between the said other supply chamber and another inlet passage, and opposed actuating surfaces on the valve subjected intermittently to compression flowing from the piston chamber for throwing the valve and subjected to pressure fluid, flowing to the inlet passages for holding the valve in its lim- WALTER E. CARR. 

